Heat motor



July 13,1937. M. PERSONS HEAT MOTOR Filed Sept. 21, 1934 %zmff 10 simple to manufacture.

Patented July 13, 1931 PATENT oF IcE HEAT MOTOR Lawrence M. Persons,

a corporation of Iowa Des Moines, Iowa, assignor' to Penn Electric Switch 00.,

Des Moines, Iowa,

Application September 21,1934, Serial No. 744,934

6 Claims.

An object of my'present invention is to provide an improved type of heat motor or that type of motor wherein a liquid is vaporized by an electric resistance element or other heating means to expand a bellows or the like, the bellows being operatively connected with some member such as v a valve disc to automatically control the operation thereof in accordance with the energization of the heating means, the device being comparatively A further object is to provide a heat motor which can operate much quicker than the ordinary type, my heat motor having inherent structuralfeatures for accomplishing this purpose.

More particularly it is my object to provide a heat motor comprising a boiler and an expansible member having novel operating characteristics caused by a cup-like bailie wall within the boiler of the heat motor, a riser tube for returning 2o liquid from the expansible member to the boiler and means to insure that liquidwill leave the boilerfrom the lower portion thereof and return through the riser tube.

Still a further object is to so connect the controller member with a valve disc or the like to be controlled that lost motion is permissible to allow fluctuations of the controller member caused by the peculiar operating characteristics of my heat motor without actuating the valve disc except 30 when the heating means for the boiler is deenergized.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my de 35 vice whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawing, in which: Figure 1 is a vertical sectional view through a 40 "heat motor embodying my invention and showing it connected with a valve, such as the type used for controlling the flow of gas to a gas'burner.

Figure, 1a shows a slight modification of Figure 1. I 45v Figure 2 in a diagrammatic view of my invention showing it in the normally inoperative positon.

Figure 3 is a similar diagrammatic view show- 50 position.- 1 x I Figure 4 is asiinilar diagrammatic view-showing the return from the position of Figure 3 to the position of Figure 2 when the heat motor is de- 55 energized.

mg the heat motor in'energizedand actuating Figure 5 -is a diagrammatic sectional view on the line 5-5 of Figure 1; and

Figure 6 is a diagrammatic view on the line 6-6 of Figure 5. n the accompanying drawing I have used the reference numeral I!) 'to indicate a bellows, by way of illustration, as an expansible pressure operated control member. The bellows l0 may be provided with a perforated ear l2 or the like for connection with some member to be con- 10 trolled, as will hereinafter be described. The bellows I0 preferably has its lower end sealed relative to a base l4 and its other end sealed by a head I5 from which the ear l2 extends.

A boiler I6 is mounted on the base l4 and has a resistance wire l8 wound thereon for the purpose of heating the boiler when the resistance wire is energized. In place of resistance wire, any suitable heating means may be used. Within the boiler I6 I provide-a. bafiie member which 20 is preferably cup shaped asshown in cross section in Figure 1.

Means of communication is afforded between the compartment within the bellows ill and the boiler IS in the following described manner:-A passageway 36 communicates with avalve seat 34 and with a passageway 22 extending to a check valve 24. The check valve 24 is normally seated by gravity against a seat 26. The seat 26 communicates by means of a passageway 28 with the 30 bottom of the boiler l6.

A riser tube 30 is mountedin the base l4 and communicates by means of a passageway 3| with a second check valve 32 normally seated by gravity on the seat 34. 35

A housing 31 is mounted on the base [4 to enclose the bellows and the boiler. Extending through a slot 38 in one side thereof is an arm 40 pivoted on a pin 42. By means of a link 44 the arm 40 is operatively connected with the ear I2 40 whereby movements of the bellows) swing the arm 40 for the purpose of controlling any desired apparatus.

Another device is also illustrated as being controlled by the bellows and' it will now be described: (The device mentioned is omitted from the diagrammatic showings in Figure 2, 3, and 4.) 4 w A pin 46' depends from the bellows he ad I5 and is slidably mounted in a sleeve 48 extending upwardly from the base I4. The sleeve 48 is provided with a guide opening 50 and the pin 46 may besecured, as by a screw 52, with the head of the bellows to seal the pin 46 against the escape of liquid within the bellows. I provide a second bellows 54 having a head 35 sealed relative to the head l5 and having its lower end sealed to the base. I

5 A sleeve 56 surrounds the pin 46 and a return spring 51 is interposed between the upper end of this sleeve and the top of the sleeve 48 for the purpose of normally constraining the bellows l0 toward collapsed position. A washer 59 is held assembled on the pin 14 and has cars 58 extending from opposite sides thereof. The cars 58 are connected by two pairs of springs Eli and 60a with snap acting yokes 62. The yokes 62 are provided with sharpened ends 64 oscillatable in notches 65 of. brackets 66.

A valve device 68 seated against a valve seat I0 of a valve 12. The disc 6; has a socket-like sleeve 16 to slidably receive the element 14, a spring 18 being interposed between the two for normally constraining the element 14 upwardly relative to the disc 68. Projections 8t and 82 are'provided on the valve disc 68 between whi h the yokes 62 operate.

Practical operation The elementary operation of the present day heat motor involves the operation of a bellows or the like by the depression of a liquid in a boiler by heating and thereby boiling part of that liquid with an electric heater wound round the boiler. The bellows remains in operative position as long as heat is applied. The large size of the heater required to boil the liquid and thereby operate the bellows from a cold start in a reasonable length of time causes the boiler to be heated to an excessively high temperature. If the heater is maintained energized, the bellows remains in the expanded position. This accumulates heat which must be dissipated after the heater is deenergized before the bellows can contract to its original position. The time required for heat dissipation causes a slow return of the bellows and when the bellows is connected with a gas valve of a furnace, for instance, the slow return is objectionable. Also the opening operation of the gas valve is slowas a large amount of the liquid in the boiler must be heated before vaporization takes place.

The particular construction I illustrate overcomes such slow action causing the heat motor to complete a cycle of operation in less than a minute which is actually from fifteen to twenty times faster than the ordinary heat motor. It should here be mentioned that I employ suitable liquid substantialy filling the boiler' l6 and the bellows lo when in collapsedmosition, as illustrated in Figure 2.

In operation, when the heating element I8 is energized, it willcommence to boil the liquid in the boiler l6 causing it to recede. from tion in Figure 2 and quently. expand. The prevent convection currents from stirring the liquid in the boiler so as thus to speed up the the posithe bellows lfl to consebe ,used to further increase the convection current prevention, if desired.

As the surface of the liquid recedes .from. the A cession of the liquidfrom the boiler and cons'equently the pressure, thus causing the greater 46 by a stud-like element is provided and normally pressure and stopping If the heating element is energized a sufficient down the walls of the boiler.

baffle wall 20 will. act' to.

initial vaporization of theliquid. It will be obviousthat instead of one baflle wall several may muchquicker. than otherwise. This rapidly irmreases the re- 'liquid is completely evaporated from the tray,

whereupon further condensation on the surface of .the liquid causes a decrease in the pressure, whereupon the bellows ill will start to contract due to the action of the spring 51.

The liquid in receding from the boiler will pass through-the check valve 24 which will be opened bythe liquid as shown in Figure 3, and when recession stops this valve will close. When the liquid starts to return it opens the valve 32 so that the return is through the riser tube 30. A small quantity of the liquid will be deliveredthrough the tube 30 to the tray 20 wherein it becomes immediately vaporized because the heating element is still energized, thus again increasing the the return flow of liquid.

period of time this slight pumping process occurs atintervals of one ortwo minutes, thus keeping the liquid in the tray. and the top of the boiler very close to the boiling point of the liquid. This limits the temperature near the top of the boiler to substantially that of the boiling point of the liquid so that excessive heat is prevented andthe objection of slow collapse of the bellows ill is thus somewhat lessened When the heating element i8 is de-energized the boiler fiuic-kly cools from a point substantially the boiling point ofthe liquid to a point allowing condensation of the liquid in the boiler suflicient to start a return of the bellows toward a collapsed position and liquid is immediately delivered from the riser tube to the tray 20. This liquid is comparatively cool since it has been within the bellows rather than within the boiler so that, being sprayed against the baflle 20 and the wall of the boiler [6, it hastens the cooling thereof and consequently the condensing action, the tray spills over into the boiler proper and this also aids in avery rapid condensation of the liquid and the bellows practically snaps back to its initial position.

A baiiie such as 10a (see Figure la), which is not cupped, will give partiaLresults as at the start of the opening operation the action will be just as rapid but as the liquid recedes in the boiler, the heat supplied to the surface of the boiler would be gradually less and less as this heat could only reach the liquid by traveling These walls are left cold by the receding liquid. Thus the boiling of the liquid in the tray supplies a means to transfer the heat from the hottest part of the .heater in the boiler at its top to the-surface of the receding liquid.'

From the foregoing tray 20 therefore speeds up the start of the opening operation by preventing convection currents; speeds up the opening operation by providing vapor. pressure from the hottest point in the boiler; speeds up the start of the closing operation by limiting the temperature at the top of the boiler and \speeds up the closing operation by providing a large area for condensation a will be obvious that the i surface against which the returning liquid is discharged. In the latter capacity the baiiie acts somewhat like a fin of a heat exchanger. I

In the foregoing operation the action of the heat motor per se has been; described. I have found my heat motor especially adaptable for gas valves and have provided the described construction for connecting the bellows In with the gas valve for purposes which will now appear.

As the pin 46 raises, caused by the expansion of the bellows ID the inner ends of the springs 60 and 60a pass over center with respect to the notches 65 causing the yokes 62 to snap upwardly, thus leaving the projections 80 and striking the projections 82. This will open. the valve with a snap action, the springs 50 and 60a tending, after over center position is reached, to swing. the yokes 62 upwardly.

As the slight-pumping action described -in the action of the heat motor occurs after the gas valve has opened and while the heating element I8 is still energized, there will be a slight raising and lowering of the pin 46 but it will not travel far enough to move the springs 60 and 60a downwardly again past the center represented by the notches 65. Thus the yokes 62 will retain thevalve disc 68 open without any fluctuation in its position until such time as the heating element I8 is tie-energized for permitting the bellows I to quickly collapse and during the last portion of the collapsing movement cause the yokes 62 to again snap downwardly for closing the gas valve quickly.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention anditis my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which maybe reasonably included within their scope.

I claim as my invention: 1; In a heat motor, a boiler, heating means therefor, an expansible controller member communicating therewith, liquid sealed within said boiler and said expansible member, means within said boiler to prevent convection currents of the portion of the liquid within the boiler when said heating means is in operation, means for returning liquid from the expansible member to the boiler while the heating means is in operation, said means for preventing convection currents, also preventing returning liquid from condensing the vapors to an extent causing collapse of the expansible controller member and comprising a receptacle within said boiler to receive returning liquid, said receptacle being in heat conducting relation with the wall of said boiler to revaporize any liquid returned to the receptacle.

2. In a heat motor, a boiler, heating means therefor surrounding said boiler, an expansible controller member communicating therewith, liquid sealed within saidboiler and said expansible member, a battle wall within said boiler and connected with the wall thereof to prevent convection currents in the portion of the liquid within the boiler when the heating means is maintained in operation to form vapor both to drive the liquid from the boiler and into said expansible member and to keep said liquid from repansible therewith, liquid sealed within said boiler and turning to said boiler, said bafile wall having a cupped portion and means for returning liquid from the expansible member into said portion after the heating means has been so maintained in operation for a period of time and is then rendered inoperative for the purpose of allowing the liquid to return to the boiler.

3. In a heat motor, a boiler, heating means therefor, an expansible controller member communicating therewith, liquid sealed within said boiler and said expansible member, the means of communication between said boiler and said expansible member including a riser tube in said boiler for liquid returned from the expansible controller member and means to catch the returned liquid, said last means being in heat con- .ductingrelationvto the boil-er whereby it is heated by said heating means therefor and thereby quickly revaporizes any liquid returning to the,

boiler while the heating means is in operation.

4. In a heat motor, a boiler, heating means for a wall of said boiler, an expansible controller member communicating therewith, liquid sealed within said boiler and said expansible member, the means of communicationbetween said boiler and said expansible member including a densation of the liquid returning through said riser tube. V

5. In a heat motor, a boiler, heating means therefor and surrounding said boiler, an excontroller .member communicating said expansible member, the means of communication between said boiler and said expansible member including a riser tube in said boiler and two-way mechanism allowing exit of liquid from the boiler only from the bottom of the boiler and entrance thereto only through said riser tube and a bailie wall within said boiler and con-'- nected with the wall thereof to prevent convection currents and increase the condensing surface of the boiler to facilitate condensation of the liquid returning through said riser tube, said baflle wall being cupped to retain a portion of the liquid within the boiler when the liquid recedes due to operation of said heating means.

6. In a heat motor, a boiler, heating means therefor and surrounding said boiler, an expansible controller member communicating therewith, liquid sealed within said boiler and said expansible member and a baflle wall within said boiler and connected with the wall thereof to increase the condensing surface of the boiler to facilitate condensation of the liquid returning thereto when saidheating means is not in operation, said baflle wall being cupped to retain a portion of the liquid within the boiler when the liquid recedes due to operation of said heat- 

